Hannibal was a Carthaginian military commander and tactician who is popularly credited as one of the most talented commanders in history. Hannibal lived during a period of tension in the Mediterranean, when Rome (then the Roman Republic) established its supremacy over other great powers such as Carthage, the Hellenistic kingdoms of Macedon, Syracuse, and the Seleucid empire. One of his most famous achievements was at the outbreak of the Second Punic War, when he marched an army, which included war elephants, from Iberia over the Pyrenees and the Alps into northern Italy. Hannibal occupied much of Italy for 15 years, but a Roman counter-invasion of North Africa forced Hannibal to return to Carthage, where he was decisively defeated by Scipio Africanus at the Battle of Zama. Scipio studied Hannibal's tactics and brilliantly devised some of his own, and finally defeated Rome's nemesis at Zama having previously driven Hasdrubal, Hannibal's brother, out of Spain. After the war Hannibal successfully ran for the office of suffete. He enacted political and financial reforms to enable the payment of the war indemnity imposed by Rome. However, Hannibal's reforms were unpopular with members of the Carthaginian aristocracy and Rome, and he fled into voluntary exile.